"If you are one of the millions of people who watched football before this broadcast -- many of you on this network -- you know that NFL players get their brains rattled on a weekly basis and for some of them the long-term consequences may eventually offset the glory of playing the game. After a decade of denying a link between onfield concussions and brain impairment later in life, the NFL finally acknowledged the connection and is now trying to reengineer the sport to fit the medical science. It's changing the rules, trying to reinvent equipment and funding scientific research that might endanger its future both as the country's most popular sport and as a multibillion-dollar industry. Not since football was nearly banned a hundred years ago has the sport been under the microscope the way it is today and all of it has to do with matters of the brain."